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Monday, November 4, 2013

5 Ways How to Tell the Difference Between Cottonmouths (Water Moccasins) and Copperheads

Cottonmouths,
Agkistrodon piscivorus, and
Copperheads, Agkistrodon contortrix,
are venomous snakes that are closely related and frequently encountered in the United States.
Because these two species may seem similar at first glance, they are often
confused for one another. I first noticed this trend on Twitter; if you follow me there then you already know that I am frequently there helping people identify snakes (whether
they like it or not), for example:

@AlongsideWild no dude you're wrong, I know the difference between a copperhead and a cottonmouth

Cottonmouths
don’t want to bite you unless they really they have to. That’s why they’ve come
up with some impressive defensive displays. The point of these defensive
displays is to scare off predators before a bite is necessary. Fortunately, one
of the most common displays offers a great opportunity for differentiating Cottonmouths
from Copperheads. When threatened, Cottonmouths will often open up their mouths
widely and show off their namesake-white mouth (they're called Cottonmouths for a reason, after all). Copperheads can open their
mouths too, but they do so less often and their mouths are more pinkish.
Cottonmouths don’t always open their mouths either, so we can’t always use this
feature to tell them apart.

2. The color and patterning of a Cottonmouth’s body is
different than that of Copperheads.

A
recent commenter on this blog described adults Copperheads as being the
color of chocolate milk with a chocolate kiss pattern. I think that’s a great
analogy. Most Copperheads are indeed this color with a brown hourglass-banding
pattern. It is important to note though, some Copperheads may appear a little
more brown or a little more orange, depending on the individual and where it is
found.

Adult
Cottonmouths, on the other hand, often appear almost black or dark brown, much
different than adult Copperheads. However, some Cottonmouths are not so dark
that you can’t make out a pattern. Cottonmouth patterns are superficially
similar to that of Copperheads, but the hourglass bands of a Cottonmouth are
not as precise as those of Copperheads: they are messy, the lines are blurred,
and sometimes there are other shapes thrown in there as well. In general,
Cottonmouths become darker over time, obscuring their patterns. And, this
brings up an important point.

Cottonmouth

Baby
Cottonmouths are as strikingly and vividly patterned as Copperheads, they do
not become dark and lose their pattern until later in life. Just because the
patterns on a baby Agkistrodon are
clear does not mean it is a Copperhead. This is where it's important to see if the hourglasses are messy or not. Again, Copperhead bands are relatively crisp, Cottonmouth bands
are not. That said, in some regions Copperhead markings can get kind of messy, check out Kentucky animals, for example.

@AlongsideWild Well, the bright yellow tail characteristics of young copperheads would beg to differ...

Despite what you might hear elsewhere, both Cottonmouths and Copperheads have a
bright yellow or green tail tip when they are babies (they use it to lure in
prey) so the presence of this bright tail tip cannot be used to differentiate
between the species.

Cottonmouth (top) Copperhead (bottom)

3. Cottonmouths have a dark band on their face that runs through their eye.

Copperheads
do not (see comparison on right).

4. In many parts of the country, you can find
Cottonmouths or Copperheads, but not both.

In
many parts of the Southeast and Midwest of the United States, both Cottonmouths
and Copperheads can be found, in general. However, there are lots of places
where only one occurs. For example, Cottonmouths can be found throughout all of
Florida, but Copperheads are only in a bit of the panhandle. On the other hand, Copperheads are
crawling around much of the northeastern United States, but if you are traveling up the East Coast you’ll see your last Cottonmouths in Virginia. I suggest you take a look
at the range maps for Cottonmouths and Copperheads so you can determine whether you
can rule out one or both of these species when trying to identify a snake
around your home.

5. Copperheads and Cottonmouths are usually found in
different habitats.

Cottonmouths
mostly use wet and/or swampy areas while Copperheads prefer more upland and
forested habitats. This isn’t a hard and fast rule though, so it should be used
together with the other tips provided here. Cottonmouths may migrate out of their
swamps when they dry up, and I’ve seen Cottonmouths suddenly appear in new wetlands formed by recent rains (they showed up to feast on breeding
amphibians and would have had to travel across long stretches of pine
forest to get there). I’ve never seen a Copperhead in the water though; my guess is
that it’s a relatively rare occurrence.

Okay, let's put your knowledge to the test.

Try identifying each of these five snakes(without reading the comments first!).